Novochares oculatus (Sharp, 1882)

Short, Andrew Edward Z. & Giron, Jennifer C., 2023, Revision of the Neotropical water scavenger beetle genus Novochares Giron & Short (Coleoptera, Hydrophilidae, Acidocerinae), ZooKeys 1171, pp. 1-112 : 1

Novochares oculatus (Sharp, 1882)

Figs 3B , 9A-E , 10B

Helochares oculatus Sharp, 1882: 74.

Helochares (s. str.) oculatus Sharp, 1882; Fernández 1982a: 31 [specific rank confirmed; not syn. of Novochares pallidus Castelnau, as in d’Orchymont 1926: 232; not. syn. of Novochares abbreviatus Fabricius, as in d’Orchymont 1936: 10; lectotype designated]; Fernández 1989: 148 [in key]; Hansen 1999: 162 [catalog].

Novochares oculatus (Sharp, 1882); Girón and Short 2021: 205.

Type material examined.

Paralectotype (male): " Helochares ocu-/ Novochares latus D.S./ Paso Antonio. Guate/mala Champion [on card with specimen]", "Sharp Coll./ 1905.-313", "Paso Antonio,/ 400 ft./ Champion.", "B.C.A. Col. I. 2./ Helochares / Novochares oculatus ,/ Sharp.", "Brit.Mus./ USNM-1966/ EXCHANGE" (USNM; Fig. 9E ).

Additional material examined

(8 exs.). Belize: Stann Creek, Sitte Point, Possum Point Biological Station , 24.iv.1987, leg. P.J. Spangler (1, USNM) . Colombia: Magdalena: 8 km E Barranquilla , 19.iii.1969, leg. P. & P. Spangler (1, USNM) . Mexico: Jalisco: Barra de Navidad , 23.iii.1971, leg. J.R. Zimmerman (1, USNM) . Oaxaca: 31 km S Tuxtepec, Bethania, Ao. Chopan , 24.v.1981, blacklight, leg. P.J. Spangler (1, USNM) ; Sinaloa: Mazatlan , 17.vii.1963, leg. P.J. Spangler (1, USNM) . Panama: Canal Zone, Barro Colorado Island , vi.1939, leg. J. Zetek (2, USNM), same locality but 29.v.1940, at light (1, USNM) .

Differential diagnosis.

The precise morphological boundaries of this taxon are still uncertain. Its primary characteristic within the species group is its relatively large and oval distal cup of the dorsal plate of the median lobe, which bears two long arms (Fig. 9A, B ). However, there is much variation and we recommend a relatively conservative approach in making confirmed species identifications at this time (see remarks for further discussion).

Description.

Body length 6.0-6.5 mm. Coloration: Dorsal surfaces pale brown to orange-brown, sometimes with weakly paler (orange) clypeus and margins of pronotum and elytra. Head: Maxillary palps nearly 1.3 × width of head, uniformly yellow to orange in color. Thorax: Elytra without rows of serial punctures, faint rows (one dorsal and two or three lateral) of scarce and weakly marked systematic punctures barely noticeable. Prosternum medially broadly convex. Posterior elevation of mesoventrite broadly elevated, with low medial longitudinal ridge extending anteriorly. Abdomen: Apical emargination of fifth ventrite moderately deep and relatively narrow. Aedeagus: (Figs 3B , 9A-D ) Outer margin and apical region of each paramere rounded at apex and laterally pointed to hook-shaped; dorsal plate of median lobe with long and narrow neck, obliquely explanate at apical region, somewhat diamond-shaped and laterally rounded, with two laminate and slender distal arms, narrowly separated at base, apically converging, and slightly dorsally pointing; arms nearly as long as base of fork; ventral plate of median lobe triangular, moderately sclerotized.

Distribution.

Belize (new record), Colombia (new record), Costa Rica, Guatemala, Mexico (confirmed record), Panama (Fig. 10B ). All records from southern South America and the Caribbean need further review (Argentina, Brazil, Paraguay, and the Antilles [Grenada, St. Vincent]).

Remarks.

The identity of this species has been wrapped up in confusion with N. abbreviatus almost immediately after it was described (see above discussion of the Novochares abbreviatus group nomenclature). We examined the dissected male lectotype and a dissected male paralectotype male deposited in the USNM (Fig. 9D, E ; it had been exchanged between USNM and the British Museum in the 1960s). We saw a number of other specimens that had an Novochares oculatus -like aedeagus but with a range of variation around the precise shape and size of the apical region of the dorsal plate of the median lobe, as well as the shape of the paramere apices (Fig. 9F, H ). We did not have good sampling of these forms for molecular data, so were not able to use an integrated approach to explore this variation. Consequently, we have taken a very conservative approach and identified only male specimens which had genitalia that very closely matched the type material as N. oculatus . The remaining material will need to wait until more data, especially genetic data, is available. There are a number of published records of N. oculatus from Argentina, Paraguay, and southern Brazil ( Fernández 1982a; Clarkson and Ferreira Jr 2014), and while it is very much possible that N. oculatus (like N. abbreviatus ) is a very widespread Neotropical species, these reports should be treated as unconfirmed until molecular data from those localities is available.

Figures

Figure 3. Aedeagi of the Novochares abbreviatus species group along with schematic representations of the whole, the parameres (in blue), and the dorsal (in yellow) and ventral (in red) plates of the median lobe A N. abbreviatus B N. oculatus.

Figure 9. Aedeagi and habitus of the Novochares abbreviatus species group A-E N. oculatus: A-C aedeagus, Mexico D, E paralectotype from Guatemala D aedeagus E habitus F-K miscellaneous forms of aedeagi in the Novochares abbreviatus species group F, G Argentina H, I Venezuela J, K Bolivia L, M, R N. pallipes N, O N. baca A, D, F, H, J, L, N dorsal view B, M ventral view C, G, I, K, O lateral view R oblique view.

Figure 10. Distribution of Novochares abbreviatus species group A N. abbreviatus: examined specimens (red) and literature / unconfirmed records (blue) B N. oculatus: examined specimens (red) and literature / unconfirmed records (blue) C N. pallipes (red), N. latus (yellow), N. baca (blue), N. pilatus (green).